Another Apple-to-switch-Macs-to-ARM post. "Apple engineers have grown confident that the chip designs used for its mobile devices will one day be powerful enough to run its desktops and laptops, said three people with knowledge of the work, who asked to remain anonymous because the plans are confidential. Apple began using Intel chips for Macs in 2005." No idea when Apple will make the switch, but they will do it. I'm thinking 5-10 year timeframe.

There's already ARM versions of MS Office for Windows, so I don't know where you get this idea that Adobe nor MS couldn't cross-compile their software if Apple decided to support ARM on their desktop OS.

Microsoft could support ARM Mac OS X, but I imagine it would take a couple of years. And to my knowledge, Adobe doesn't have ARM versions of their applications. The amount of platform specific optimizations are probably mind boggling. Doable? Yes. Immediate? Not by a long shot.

And to my knowledge, Adobe doesn't have ARM versions of their applications.

Actually they do. And they also had PowerPC versions before Apple moved to Intel (granted out of date code, but it shows a history of supporting multiple platforms).

The amount of platform specific optimizations are probably mind boggling.

It makes very little sense to pile on CPU specific optimisations by hand - not least because it makes human coding errors massively easier to make yet harder to spot and correct, but also because packages like Office simple don't need to. Even in the case of Photoshop, most of the hardware optimisations should come in the form of GPU acceleration (GPU optimisations will reap better returns than CPU optimisations due to GPUs having better support for floating point and -lets be honest- being tailored for graphics already).

You make this big deal as if developers haven't ever had to target other CPU architectures - and I guess if you're exclusively a Windows desktop developer then that would be true - but software developers of this sort of scale routinely target other platforms so porting to new architectures shouldn't be a problem so long as the underlying OS framework remains relatively static (and OS X has proven itself there already: PPC->i686->AMD64)